In a patient suffering from angina of effort, nitroglycerin may be given sublingually because this mode of administration


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In a patient suffering from angina of effort, nitroglycerin may be given sublingually because this mode of administration

A. bypasses the coronary circulation
B. causes less reflex tachycardia than oral administration
C. improves patient compliance
D. has a decreased tendency to cause methemoglobinemia
E. avoids first-pass hepatic metabolism

Answer: E. The sublingual administration of a drug avoids its absorption
into the portal circulation and hence eliminates the possibility of first-pass
metabolism, which can often have a major impact on oral bioavailability.
Given sublingually, nitroglycerin is more effectively absorbed into the systemic circulation and has improved effectiveness in angina by this mode of
administration. Effective absorption is unlikely to decrease reflex tachycardia or propensity toward methemoglobinemia. There is no bypass of the
coronary circulation—nitrates actually decrease coronary vasospasm, which
makes them effective in variant angina